HVI-PAO in industrial lubricant and grease compositions

ABSTRACT

The invention relates to industrial lubricant and grease compositions containing high viscosity index polyalphaolefins (HVI-PAO). The use of HVI-PAOs in industrial oils and greases application provides advantages in improved shear stability, wear property, foam property, energy efficiency and improved overall performance.

FIELD OF THE INVENTION

The invention relates to industrial lubricant and grease compositionscontaining high viscosity index polyalphaolefins (HVI-PAO).

BACKGROUND OF THE INVENTION

Polyalphaolefins (PAOs) of different viscosity grades are known to beuseful in synthetic and semi-synthetic industrial oil and greaseformulations. See, for instance, Chapters 22 and 23 in Rudnick et al.,“Synthetic Lubricants and High-Performance Functional Fluids”, 2nd Ed.Marcel Dekker, Inc., N.Y. (1999). Compared to the conventional mineraloil-based products, these PAO-based products have excellentviscometrics, high and low temperature performance and energy efficiencyunder routine conditions and ordinary replacement schedules.

The viscosity-temperature relationship of a lubricating oil is one ofthe critical criteria, which must be considered when selecting alubricant for a particular application. Viscosity Index (VI) is anempirical, unitless number which indicates the rate of change in theviscosity of an oil within a given temperature range. Fluids exhibitinga relatively large change in viscosity with temperature are said to havea low viscosity index. A low VI oil, for example, will thin out atelevated temperatures faster than a high VI oil. Usually, the high VIoil is more desirable because it has higher viscosity at highertemperature, which translates into better or thicker lubrication filmsand better protection of the contacting machine elements. In anotheraspect, as the oil operating temperature decreases, the viscosity of ahigh VI oil will not increase as much as the viscosity of a low VI oil.This is advantageous because the excessively high viscosity of the lowVI oil will decrease the efficiency of the operating machine. Thus ahigh VI oil has performance advantages in both high and low temperatureoperation. VI is determined according to ASTM method D 2270-93 [1998].VI is related to kinematic viscosities measured at 40° C. and 100° C.using ASTM Method D 445-01.

PAOs comprise a class of hydrocarbons manufactured by the catalyticoligomerization (polymerization to low molecular weight products) oflinear α-olefins typically ranging from 1-hexene to 1-octadecene, moretypically from 1-octene to 1-dodecene, with 1-decene as the most commonand often preferred material. Examples of these fluids are described, byway of example, in U.S. Pat. Nos. 6,824,671 and 4,827,073, althoughpolymers of lower olefins such as ethylene and propylene may also beused, especially copolymers of ethylene with higher olefins, asdescribed in U.S. Pat. Nos. 4,956,122 or 4,990,709 and the patentsreferred to therein.

High viscosity index polyalphaolefin (HVI-PAO) are prepared by, forinstance, polymerization of alpha-olefins using reduced metal oxidecatalysts (e.g., chromium) such as described in U.S. Pat. Nos.4,827,064; 4,827,073; 4,990,771; 5,012,020; and 5,264,642. TheseHVI-PAOs are characterized by having a high viscosity index (VI) and oneor more of the following characteristics: a branch ratio of less than0.19, a weight average molecular weight of between 300 and 45,000, anumber average molecular weight of between 300 and 18,000, a molecularweight distribution of between 1 and 5, and pour point below −15° C.Measured in carbon number, these molecules range from C30 to C1300.Viscosities of the HVI-PAO oligomers measured at 100° C. range from 3centistokes (“cSt”) to 15,000 cSt. These HVI-PAOs have been used asbasestocks since their commercial production and are commerciallyavailable, such as for instance SpectraSyn Ultra™ fluid, from ExxonMobilChemical Co.

Another advantageous property of these HVI-PAOs is that, while lowermolecular weight unsaturated oligomers are typically and preferablyhydrogenated to produce thermally and oxidatively stable materials,higher molecular weight unsaturated HVI-PAO oligomers useful aslubricant are sufficiently thermally and oxidatively stable to beutilized without hydrogenation and, optionally, may be so employed.

HVI-PAO materials have been used for formulating oils for internalcombustion engines. By way of example, WO 00/58423 teaches highperformance oil comprising a first and second polymer of differingmolecular weights dissolved in a basestock of low viscosity. The firstpolymer is a high viscoelastic polymer, preferably an HVI-PAO. Thebasestock used generally has a viscosity of below 10 cSt at 100° C. TheHVI-PAO is “normally present in relatively small amounts”, e.g., 0.1 toabout 25 wt % in the total finished product. Also included in thefinished product is a polymeric thickener, normally based on blockcopolymers produced by the anionic polymerization of unsaturatedmonomers including styrene, butadiene, and isoprene. A “conventional”additive package, containing dispersant, detergents, anti-wear, orantioxidants such as phenolic and/or amine type antioxidants is alsoadded.

See also U.S. Pat. Nos. 4,180,575; 4,827,064; 4,827,073; 4,912,272;4,990,771; 5,012,020; 5,264,642; 6,087,307; 6,180,575; WO 03/09136; WO2003071369A; U.S. Patent Application No. 2005/0059563; and LubricationEngineers, 55/8, 45 (1999).

Industrial gear oils have to meet the following requirements: excellentresistance to aging and oxidation, low foaming tendency, goodload-carrying capacity, neutrality toward the materials involved(ferrous and nonferrous metals, seals, paints), suitability for highand/or low temperatures, and good viscosity-temperature behavior; geargreases, in contrast, are required to ensure the following: goodadhesion, low oil separation, low starting torques, compatibility withsynthetic materials, and noise dampening (c.f., Rudnick et al., supra).Heretofore, a universal gear lubricant meeting all these requirements isnot, as far as the present inventors are aware, commercially available.This requires that lubricant manufacturers develop different types offormulations with properties satisfying individual operating needs foreach application.

The present inventors have surprisingly discovered a novel industriallubricant and grease composition comprising a high viscosity indexpolyalphaolefin (HVI-PAO).

SUMMARY OF THE INVENTION

The invention is directed to oil and grease formulations for industrialuse comprising a high viscosity index polyalphaolefin (HVI-PAO).

The HVI-PAOs useful in the present invention are characterized by havinga high viscosity index (VI), preferably 130 or greater, more preferablygreater than 160, and still more preferably 165 or greater, as measuredby ASTM D2270, and one or more of the following characteristics: abranch ratio of less than 0.19, a weight average molecular weight ofbetween 300 and 45,000, a number average molecular weight of between 300and 18,000, a molecular weight distribution of between 1 and 5, and pourpoint below −15° C. In an embodiment, these HVI-PAOs may be furthercharacterized by carbon number ranging from C30 to C1300. In anotherembodiment, these HVI-PAOs may be characerized by kinematic viscositiesmeasured at 100° C. ranging from 3 centistokes (“cSt”) to 15,000 cSt, asmeasured by ASTM D445.

In embodiments, the HVI-PAOs useful in the present invention may beprepared by non-isomerization polymerization of alpha-olefins usingreduced metal oxide catalysts (e.g., reduced chromium on silica gel),zeolite catalysts, activated metallocene catalysts, or Zeigler-Natta(“ZN”) catalyst.

In preferred embodiments, the formulations according to the presentinvention are used as gear oils, circulating oils, compressors oils,hydraulic oils, refrigeration lubes, metalworking fluids and greases.

In an embodiment the formulations according to the invention furthercomprise one or a mixture of several grades of the HVI-PAO by itself orwith at least one ingredient selected from PAOs, polymers or oligomersfrom ethylene/alphaolefins, esters, polyethers, polyether esters,alkylaromatic fluids, suitable polyalkylene glycols, Group I basestocks, Group II or Group III hydroprocessed base stocks, or lubricantsderived from hydroisomerized waxy stocks (such as slack wax or waxyFischer-Tropsch hydrocarbons, for example), or other suitable lubricantbase stocks.

In another embodiment, the formulations also comprise one or more ofadditives selected from anti-oxidants, viscosity modifiers, pour pointdepressants, anti-wear agents, extreme pressure additives, defoamants orantifoamants, friction modifiers, dispersants, detergents, corrosioninhibitors, tackifiers, seal swell additives, biocides, demulsifiers,and metal passivators. However, a particular advantage of formulationsaccording to the present invention is that certain conventionaladditives for industrial lubricants and greases are not required,particularly polymeric thickeners or other thickening fluids, e.g.,polyisobutylenes, conventional poly-alpha-olefins (PAO) or VI improvers.

It is an object of the invention to provide formulations useful asindustrial oils and/or greases having one or more of the followingcharaceristics: high thermal and oxidative stabilities, low friction,superior anti-wear property, shear stability, energy efficiency, lowfoaming property, low traction, long-term property stability even afteruse or aging, and excellent water separability properties anddemulsibility properties.

It is another object of the invention to provide industrial oil and/orgreases having one or more performance improvements selected fromoperation lifetime, energy efficiency, machine protection andreliability.

These and other objects, features, and advantages will become apparentas reference is made to the following detailed description, preferredembodiments, specific examples, and appended claims.

DETAILED DESCRIPTION

According to the invention, formulations for use as industrial oils andgreases are provided comprising a high viscosity index PAO (HVI-PAO).

The HVI-PAOs useful in the present invention are characterized by havinga high viscosity index (VI), preferably 130 or greater, more preferablygreater than 160, and still more preferably 165 or greater, yet morepreferably 200 or greater, and yet still more preferably 250 or greater.An upper limit on VI, while not critical to the characterization ofHVI-PAOs useful in the present inventioin, is about 350. VI as usedherein are measured according to ASTM D2270.

The HVI-PAOs generally can be further characterized by one or more ofthe following: C30-C1300 hydrocarbons, a branch ratio of less than 0.19,a weight average molecular weight of between 300 and 45,000, a numberaverage molecular weight of between 300 and 18,000, a molecular weightdistribution of between 1 and 5.

Particularly preferred HVI-PAOs are fluids with 100° C. kinematicviscosity ranging from 5 to 3000 centistokes (cSt). The term “kinematicviscosity” as used herein will be referred to simply as viscosity,unless otherwise noted, and will be the viscosity determined accordingto ASTM D445 at the temperature specified, usually 100° C. When notemperature is mentioned, 100° C. should be inferred.

In embodiments, viscosities of the HVI-PAO oligomers measured at 100° C.range from 3 cSt to 15,000 cSt, or 3 cSt to 5,000 cSt, or 3 cSt to 1000cSt, or 725 cSt to 15,000 cSt, or 20 cSt to 3000 cSt.

The HVI-PAOs may be further characterized, in an embodiment, by a lowpour point, generally below −15° C., as determined by ASTM D97.

The term “PAO” in HVI-PAOs means, as is generally accepted in the art,an oligomer (low molecular weight polymer) of one or more alpha olefins,such as 1-decene. In embodiments, the HVI-PAOs of the invention may befurther characterized as hydrocarbon compositions comprising theoligomers of one or more 1-alkenes selected from C6-C36 1-alkenes, morepreferably C6-C20, still more preferably C6-C14. Examples of the feedscan be 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, etc., ormixtures thereof, such as one or more of C6 to C36 1-alkenes, or one ormore C6 to C20 1-alkenes, or one or more C6 to C14 alkenes, or mixturesof specific 1-alkenes, such as a mixture of C6 and C12 1-alkenes, amixture of C6 and C14 1-alkenes, a mixture of C6 and C16 1-alkenes, amixture of C6 and C18 1-alkenes, a mixture of C8 and C10 1-alkenes, amixture of C8 and C12 1-alkenes, or a feed comprising at least two1-alkenes selected from the group consisting of C8, C10 and C121-alkenes, and so forth, although oligomers of lower olefins such asethylene and propylene may also be used, including copolymers ofethylene with higher olefins, as described in U.S. Pat. No. 4,956,122.

Preferred methods of making the HVI-PAO fluids useful in the presentinvention can be made from several process catalysts. Example catalystsare supported solid reduced Group VIB metal (e.g. chromium) catalystunder oligomerization conditions at a temperature of about roomtemperature to 250° C., or metallocene catalysts. Numerous patentsdescribe the preparation of HVI-PAO useful in the present invention,such as U.S. Pat. Nos. 4,827,064; 4,827,073; 4,912,272; 4,914,254;4,926,004; 4,967,032; and 5,012,020. Additional methods of preparing aHVI-PAO useful in the present invention are described herein.

In preferred embodiments for preparation of HVI-PAOs useful in thepresent invention, the lube products usually are distilled to remove anylow molecular weight compositions such as those boiling below about 600°F. (about 315° C.), or with carbon number less than C20, if they areproduced from the polymerization reaction or are carried over from thestarting material. This distillation step usually improves thevolatility of the finished fluids. In certain special applications, orwhen no low boiling fraction is present in the reaction mixture, thisdistillation is not necessary. Thus, in preferred embodiments, the wholereaction product after removing any solvent or starting material can beused as lube base stock or for the further treatments.

The lube fluids made directly from the polymerization or oligomerizationprocess usually have unsaturated double bonds or have olefinic molecularstructure. The amount of double bonds or unsaturation or olefiniccomponents can be measured by several methods, such as bromine number(ASTM 1159), bromine index (ASTM D2710) or other suitable analyticalmethods, such as NMR, IR, and the like, well-known per se to one ofordinary skill in the art. The amount of the double bond or the amountof olefinic compositions depends on several factors—the degree ofpolymerization, the amount of hydrogen present during the polymerizationprocess and the amount of other promoters which participate in thetermination steps of the polymerization process, or other agents presentin the process. Usually, the amount of double bonds or the amount ofolefinic components is decreased by the higher degree of polymerization,the higher amount of hydrogen gas present in the polymerization process,or the higher amount of promoters participating in the terminationsteps.

Oxidative stability and light or UV stability of fluids usually improveswhen the amount of unsaturation double bonds or olefinic contents isreduced. Therefore in preferred embodiments, it is necessary to furtherhydrotreat the polymer if they have high degree of unsaturation.Usually, the fluids with bromine number of less than 5, as measured byASTM D1159, is suitable for high quality base stock applications of theinvention. Fluids with bromine number of less than 3 or 2 are preferred.The most preferred range is less than 1 or less than 0.1.

In embodiments, the lube products in the production of the HVI-PAOs arehydrotreated to reduce unsaturation. This may be done by methodswell-known per se in literature (e.g., U.S. Pat. No. 4,827,073, example16). In some HVI-PAO products, the fluids made directly from thepolymerization already have very low degree of unsaturation, such asthose with viscosities greater than 150 cSt at 100° C. They have brominenumbers less than 5 or even below 2. In these cases, the direct productmay be used without hydrotreating. Thus, hydrotreatment of the HVI-PAOproduct is optional, depending on the method used to make the HVI-PAOand the end use.

The present invention also comprises lubricant compositions containinglubricant base stocks and additives per se known to be useful forindustrial lubricant application and greases.

Industrial lubricants comprise a wide variety of products. Examples ofindustrial lubricants are gear lubrication oils, hydraulic oils,compressor oils, circulation oils, paper machine oils, and the like.

Depending on applications, industrial lubricants can have wide viscosityrange, from 2 cSt to 1650 cSt at 100° C., which are much wider than theviscosity specifications for automotive engine oils. For most industrialoils, viscosity is a significant criterion. General machinery oils areclassified according to ISO Standard 3448 viscosity specification.

Viscosities of base stocks used to formulate industrial lubricants havecritical effect on finished lubricant performance for industrialmachinery application. For example, high speed and lightly loaded plainbearings can use a low viscosity lubricant. The viscosity film generatedby such low viscosity fluid is enough to ensure hydrodynamiclubrication. However, higher loadings and lower speed equipment requireshigher viscosity oils to provide stronger and thicker lubricating filmfor protection. There are many ways to achieve wide viscosity range,blending of commonly available low viscosity fluids, such as the 100 SUSsolvent-refined base stocks or low viscosity Group IV or Group V basestocks, with high viscosity fluids, such as the commonly availablebright stock, high viscosity PAO, such as SpectraSyn™ 100 fluid, highviscosity polyisobutylenes, or with viscosity improvers or viscosityindex improvers. The quality of the high viscosity base stock iscritical to the property and the performance of the finished lubricants.

The lube base stocks used in industrial lubricant formulations compriseat least some amount of single viscosity grade or a mixture of severalviscosity grades of HVI-PAO fluids. The total HVI-PAO composition canranged from 1% to 99 wt %, depending on the desirable viscosity gradesof the finished lube, the starting viscosity grade of the HVI-PAO or theviscosities of other components present in the finished lube. Inpreferred embodiments, the amount of HVI-PAO present can range from 1 to90 wt %, or 15 to 50 wt %, or 15 to 45 wt %, or 50 to 99 wt %, or 50 to90 wt %, or 55 to 90 wt %

Basestocks that may be blended with the HVI-PAOs of the inventioninclude those that fall into any of the well-known American PetroleumInstitute (API) categories of Group I through Group V. The API definesGroup I stocks as solvent-refined mineral oils. Group I stocks containthe least saturates and highest amount of sulfur and generally have thelowest viscosity indices. Group I defines the bottom tier of lubricantperformance. Group II and III stocks are high viscosity index and veryhigh viscosity index base stocks, respectively. The Group III oilsgenerally contain fewer unsaturates and sulfur than the Group II oils.With regard to certain characteristics, both Group II and Group III oilsperform better than Group I oils, particularly in the area of thermaland oxidative stability.

Group IV stocks consist of polyalphaolefins, which are produced via thecatalytic oligomerization of linear alphaolefins (LAOs), particularlyLAOs selected from C5-C14 alphaolefins, preferably from 1-hexene to1-tetradecene, more preferably from 1-octene to 1-dodecene, and mixturesthereof, with 1-decene being the preferred material, although oligomersof lower olefins such as ethylene and propylene, oligomers ofethylene/butene-1 and isobutylene/butene-1, and oligomers of ethylenewith other higher olefins, as described in U.S. Pat. No. 4,956,122 andthe patents referred to therein, and the like may also be used. PAOsoffer superior volatility, thermal stability, and pour pointcharacteristics to those base oils in Group I, II, and III.

Group V includes all the other base stocks not included in Groups Ithrough IV. Group V base stocks includes the important group oflubricants based on or derived from esters. It also includes alkylatedaromatics, polyalkylene glycols (PAGs), etc.

Particularly preferred base stocks to blend with HVI-PAO include the APIGroup I base stocks with viscosity ranging from 3 cSt to 50 cSt, GroupII and III hydroprocessed base stocks (see, for example, U.S. Pat. Nos.5,885,438, 5,643,440, and 5,358,628), Group IV PAOs such as thosedescribed in U.S. Pat. Nos. 4,149,178, and 3,742,082, and fluidsprepared from polymerization of internal olefins (also namedpolyinternal olefins or PIO), or lubes produced from Fischer-Tropschhydrocarbon synthesis process followed by suitable hydroisomerizationprocess as described in U.S. Pat. No. 6,332,974.

In embodiments, one or more of the aforementioned Group I to Vbasestocks may be blended with the HVI-PAO of the present invention, inthe amount of 1% to 99 wt %, in embodiments from 1 to 90 wt %, or 50 to99 wt %, or 55 to 90 wt %, or 1 to 50 wt %, or 1 to 45 wt %, or 5 to 50wt %, or 5 to 45 wt %. Often, one or multiple of these other base stocksare chosen to blend with HVI-PAO to obtain the optimized viscometricsand the performance. Further, preferred embodiments relate to theviscosity index of the base stocks usable as blending components in thisinvention, where in some instances the viscosity index is preferably 80or greater, more preferably 100 or greater, and even more preferably 120or greater. Additionally, in certain particular instances, viscosityindex of these base stocks may be preferably 130 or greater, morepreferably 135 or greater, and even more preferably 140 or greater

In addition to these fluids described above, in a preferred embodiment asecond class of fluids, selected to be different from the fluidsdiscussed above, and preferably having a higher polarity is also addedto the formulation. The polarity of a fluid may be determined by one ofordinary skill in the art, such as by aniline points as measured by ASTMD611 method. Usually fluids with higher polarity will have lower anilinepoints. Fluids with lower polarity will have higher aniline points. Mostpolar fluids will have aniline points of less than 100° C. In preferredembodiments, such fluids are selected from the API Group V base stocks.Examples of these Group V fluids include alkylbenzenes (such as thosedescribed in U.S. Pat. Nos. 6,429,345, 4,658,072), and alkylnaphthalenes(e.g., U.S. Pat. Nos. 4,604,491, and 5,602,086). Other alkylatedaromatics are described in “Synthetic Lubricants and High PerformanceFunctional Fluids”, M. M Wu, Chapter 7, (L. R. Rudnick and R. L. Shubkin[ed.)), Marcel Dekker, N.Y. 1999.

Also included in this class and with very desirable lubricatingcharacteristics are the alkylated aromatic compounds including thealkylated diphenyl compounds such as the alkylated diphenyl oxides,alkylated diphenyl sulfides and alkylated diphenyl methanes and thealkylated phenoxathins as well as the alkylthiophenes, alkyl benzofuransand the ethers of sulfur-containing aromatics. Lubricant blendcomponents of this type are described, for example, in U.S. Pat. Nos.5,552,071; 5,171,195; 5,395,538; 5,344,578; 5,371,248 and EP 815187.

Other Group V fluids that are suitable for use as blend componentsinclude polyalkylene glycols (PAGs), partially or fully ether- or esterend-capped PAGs. Ester base stocks may also used as co-base stocks informulations according to the invention. These esters can be prepared,for instance, by dehydration of mono-acids, di-acids, tri-acids withalcohols with mono-, di- or multi-alcohols. Preferred acids includeC5-C30 monobasic acids, more preferably 2-ethylhexanoic acid, isoheptyl,isopentyl, and capric acids, and di-basic acids, more preferably adipic,fumaric, sebacic, azelaic, maleic, phthalic, and terephthalic acids. Thealcohols can be any of the suitable mono-alcohols or polyols. Preferredexamples are 2-ethylhexanol, iso-tridecanols, neopentyl glycol,trimethylol ethane, 2-methyl-2-propyl- 1,3-propanediol, trimethylolpropane, pentaerythritol, and dipentaerythritol. Preparation, propertiesand use of these alcohols are summarized in Chapter 3 of Rudnick et al.,supra.

The secondary component of the base stock, if used, is typically used inan amount of about 1 wt % up to no more than about 50 wt % of the totalcomposition, and in embodiments from about 1 wt % up to no more thanabout 20 wt %. This contrasts with automotive gear applications, whereinup to 75% of formulations comprises similar components. Alkylnaphthalenes are preferably used in amounts from about 5 to about 25 wt%, preferably about 10 to about 25 wt. %. Alkylbenzenes and other alkylaromatics may be used in the same amounts although it has been foundthat the alkylnaphthalenes in some lubricant formulations are superiorin oxidative performance in certain applications. PAG or esters areusually used in amount of about 1 wt % to no more than about 40 wt %, inembodiments no more than 20 wt % and in other embodiments less than 10wt % or even less than 5 wt %.

The present inventors have found that using these secondary Group V basestocks usually improve one or several of the finished lubricant productproperties, such as the viscosity, solvency, seal swell, clarity,lubricity, oxidative stability, and the like, of the finished lubricantproducts.

The viscosity grade of the final product is adjusted by suitableblending of base stock components of differing viscosities. In manyconventional industrial lubricant formulations, thickeners are used toincrease viscosity. One particular advantage of the present invention isthat thickeners are not necessary and in preferred embodiments nothickeners are used. HVI-PAO fluids of different viscosity grades aremost suitably used to achieve wide finished viscosity grades withsignificant performance advantages. Usually, differing amounts of thevarious basestock components (primary hydrocarbon base stocks, secondarybase stock and any additional base stock components) of differentviscosities, may be suitably blended together to obtain a base stockblend with a viscosity appropriate for blending with the othercomponents (such as described below) of the finished lubricant. This maybe determined by one of ordinary skill in the art in possession of thepresent disclosure without undue experimentation. The viscosity gradesfor the final product are preferably in the range of ISO 2 to ISO 1000or even higher for industrial gear lubricant applications, for example,up to about ISO 46,000. For the lower viscosity grades, typically fromISO 2 to ISO 100, the viscosity of the combined base stocks will beslightly higher than that of the finished product, typically from ISO 2to about ISO 220 but in the more viscous grades up to ISO 46,000, theadditives will frequently decrease the viscosity of the base stock blendto a slightly lower value. With a ISO 680 grade lubricant, for example,the base stock blend might be about 780-800 cSt (at 40° C.) depending onthe nature and content of the additives.

In conventional formulations, the viscosity of the final product may bebrought to the desired grade by the use of polymeric thickenersespecially in the product with the more viscous grades, e.g. from ISO680 to ISO 46,000. Typical thickeners which may be used include thepolyisobutylenes, as well as ethylene-propylene polymers,polymethacrylates and various diene block polymers and copolymers,polyolefins and polyalkylstyrenes. These thickeners are commonly used asviscosity index improvers (VIs) or viscosity index modifiers (VIMs) sothat members of this class conventionally confer a useful effect on thetemperature-viscosity relationship. Although optionally used informulations according to the present invention, such components may beblended according commercial market requirement, equipment builderspecifications to produce products of the final desired viscosity grade.Typical commercially available viscosity index improvers arepolyisobutylenes, polymerized and co-polymerized alkyl methacrylates,and mixed esters of styrene maleic anhydride interpolymers reacted withnitrogen containing compounds.

The polyisobutenes, normally with a number average or weight averagemolecular weight from 10,000 to 15,000, are a commercially importantclass of VI improvers and generally confer strong viscosity increases asa result of their molecular structure. The diene polymers which arenormally copolymers of 1,3-dienes such as butadiene or isoprene, eitheralone or copolymerized with styrene are also an important classcommercially, with typical members of this class sold under names suchas Shelivis™. The statistical polymers are usually produced frombutadiene and styrene while the block copolymers are normally derivedfrom butadiene/isoprene and isoprene/styrene combinations. Thesepolymers are normally subjected to hydrogenation to remove residualdiene unsaturation and to improve stability. The polymethacrylates,normally with number average or weight average molecular weights from15,000 to 25,000, represent another commercially important class ofthickeners and are widely commercially available under designations suchas Acryloid™.

One class of polymeric thickeners is the block copolymers produced bythe anionic polymerization of unsaturated monomers including styrene,butadiene, and isoprene. Copolymers of this type are described, forinstance, in U.S. Pat. Nos. 5,187,236; 5,268,427; 5,276,100; 5,292,820;5,352,743; 5,359,009; 5,376,722 and 5,399,629. Block copolymers may belinear or star type copolymers and for the present purposes, the linearblock polymers are preferred. The preferred polymers are theisoprene-butadiene and isoprene-styrene anionic diblock and triblockcopolymers. Particularly preferred high molecular weight polymericcomponents are the ones sold under the designation Shelivis™ 40,Shelivis™ 50 and Shelivis™ 90 by Infenium Chemical Company, which arelinear anionic copolymers. Of these, Shelivis™ 50 is an anionic diblockcopolymer and Shelivis™ 200, Shelivis™ 260 and Shelivis™ 300 are starcopolymers.

Some thickeners may be classified as dispersant-viscosity indexmodifiers because of their dual function, as described in U.S. Pat. No.4,594,378. The dispersant-viscosity index modifiers disclosed in the'378 patent are the nitrogen-containing esters of carboxylic-containinginterpolymers and the oil-soluble acrylate-polymerization products ofacrylate esters, alone or in combination. Commercially availabledispersant-viscosity index modifiers are sold under trade namesAcryloid™ 1263 and 1265 by Rohm and Haas, Viscoplex™ 5151 and 5089 byRohm-GMBHO™ Registered TM and Lubrizol™ 3702 and 3715.

Antioxidants, although optional, may be used to improve the oxidativestability of formulations according to the present invention. A widerange of commercially available materials is suitable. The most commontypes of antioxidant which may be used in the present compositions arethe phenolic antioxidants, the amine type antioxidants, the alkylaromatic sulfides, phosphorus compounds such as the phosphites andphosphonic acid esters and the sulfur-phosphorus compounds such as thedithiophosphates and other types such as the dialkyl dithiocarbamates,e.g. methylene bis(di-n-butyl) dithiocarbamate. They may be usedindividually by type or in combination with one another. Mixtures ofdifferent types of phenols or amines are particularly preferred.

The preferred sulfur compounds which are optionally added tocompositions according to the present invention for improved antioxidantperformance include the dialkyl sulfides such as dibenzyl sulfide,polysulfides, diaryl sulfides, modified thiols, mercaptobenzimidazoles,thiophene derivatives, xanthogenates, and thioglycols.

Phenolic antioxidants which may be used in the present lubricants maysuitably be ashless (metal-free) phenolic compounds or neutral or basicmetal salts of certain phenolic compounds. The amount of phenoliccompound incorporated into the lubricant fluid may vary over a widerange depending upon the particular utility for which the phenoliccompound is added. In general, from about 0.1 to about 10% by weight ofthe phenolic compound will be included in the formulation. More often,the amount is from about 0.1 to about 5%, or about 1 wt % to about 2 wt%. Percentages used herein are based on the total formulation unlessotherwise specified.

The preferred phenolic compounds are the hindered phenolics which arethe ones which contain a sterically hindered hydroxyl group, and theseinclude those derivatives of dihydroxy aryl compounds in which thehydroxyl groups are in the o-or p-position to each other. Typicalphenolic antioxidants include the hindered phenols substituted with C6alkyl groups and the alkylene coupled derivatives of these hinderedphenols. Examples of phenolic materials of this type is2-t-butyl4-heptyl phenol; 2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecylphenol; 2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;2-methyl-6di-t-butyl-4-heptyl phenol; and2-methyl-6-di-t-butyl-4-dodecyl phenol. Examples of ortho coupledphenols include: 2,2′-bis(6t-butyl-4-heptyl phenol);2,2′-bis(6-t-butyl-4-octyl phenol); and 2,2′-bis(6-t-butyl4-dodecylphenol). Sulfur containing phenolics can also be used to greatadvantage. The sulfur can be present as either aromatic or aliphaticsulfur within the phenolic antioxidant molecule.

Non-phenolic oxidation inhibitors, especially the aromatic amineantioxidants may also be used either as such or in combination with thephenolics. Typical examples of non-phenolic antioxidants include:alkylated and non-alkylated aromatic amines such as the aromaticmonoamines of the formula R³R⁴R⁵N where R³ is an aliphatic, aromatic orsubstituted aromatic group, R⁴ is an aromatic or a substituted aromaticgroup, and R is H, alkyl, aryl or R⁶S(O)xR⁷ where R⁶ is an alkylene,alkenylene, or aralkylene group, R⁷ is a higher alkyl group, or analkenyl, aryl, or alkaryl group, and x is 0, 1 or 2. The aliphatic groupR³ may contain from 1 to about 20 carbon atoms, and preferably containsfrom 6 to 12 carbon atoms. The aliphatic group is a saturated aliphaticgroup. Preferably, both R³ and R⁴ are aromatic or substituted aromaticgroups, and the aromatic group may be a fused ring aromatic group suchas naphthyl. Aromatic groups R³ and R⁴ may be joined together with othergroups such as S.

Typical aromatic amines antioxidants have alkyl or aryl substituentgroups of at least 6 carbon atoms. Examples of aliphatic groups includehexyl, heptyl, octyl, nonyl, and decyl. Examples of aryl groups includestyrenated or substituted-styrenated groups. Generally, the aliphaticgroups will not contain more than 14 carbon atoms. The general types ofamine antioxidants useful in the present compositions includediphenylamines, phenyl naphthylamines, phenothiazines, imidodibenzylsand diphenyl phenylene diamines. Mixtures of two or more aromatic aminesare also useful. Polymeric amine antioxidants can also be used.Particular examples of aromatic amine antioxidants useful in the presentinvention include: p,p′-dioctyidiphenylamine;octylphenyl-beta-naphthylamine; t-octylphenyl-alpha-naphthylamine;phenyl-alphanaphthylamine; phenyl-beta-naphthylamine; p-octylphenyl-alpha-naphthylamine; 4-octylphenyl-1-octyl-beta-naphthylamine.

Typical of the dialkyl dithiophosphate salts which may be used are thezinc dialkyl dithiophosphates, especially the zinc dioctyl and zincdibenzyl dithiophosphates. These salts are often used as anti-wearagents but they have also been shown to possess antioxidantfunctionality, especially when used as a co-antioxidant in combinationwith an oil-soluble copper salt. Copper salts which may be used in thisway as antioxidants in combination with the phosphorus and zinccompounds such as zinc dialkyl dithiophosphates include the copper saltsof carboxylic adds such as stearic add, palmitic acid and oleic acid,copper phenates, copper sulfonates, copper acetylacetonates, coppernaphthenates from naphthenic acids typically having a number average orweight average molecular weight of 200 to 500 and the copperdithiocarbamates and copper dialkyl dithiophosphates where the copperhas been substituted for zinc. Copper salts of this type and their useas antioxidants are described in U.S. Pat. No. 4,867,890.

Normally, the total amount of antioxidant will not exceed 10 wt. % ofthe total composition and normally is rather less, below 5 wt. %.Usually, from 0.5 to 2 wt. % antioxidant is suitable although forcertain applications more may be used if desired.

Inhibitor Package

An inhibitor package is used to provide the desired balance of anti-wearand anti-rust/anti-corrosion properties. One component of this packageis a substituted benzotriazolelamine phosphate adduct and the other is atri-substituted phosphate, especially a triaryl phosphate such as cresyldiphenylphosphate, a known material which is commercially available.This component is typically present in minor amounts up to 5 wt. % ofthe composition. Normally less than 3% e.g. from 0.5 to 2 wt. % of thetotal composition is adequate to provide the desired anti-wearperformance.

The second component of the anti-wear/anti-rust package is an adduct ofbenzotriazole or a substituted benzotriazole with an amine phosphateadduct which also provides antiwear and anti oxidation performance.Certain multifunctional adducts of this kind (with aromatic amines) aredescribed in U.S. Pat. No. 4,511,481 to which reference is made for adescription of these adducts together with the method by which they maybe prepared. Briefly, these adducts comprise a substitutedbenzotriazole. i.e. an alkyl-substituted benzotriazole where thesubstituent R is hydrogen or lower alkyl, C₁ to C₆, preferably CH₃. Thepreferred triazole is tolyl triazole (TTZ). For convenience, thiscomponent will be referred to as TTZ here although other benzotriazolesmay also be used, as described in U.S. Pat. No. 4,511,481.

The amine component of the adduct may be an aromatic amine phosphatesalt of the formula set out in U.S. Pat. No. 4,511,481, i.e., a triazoleadduct of an amine phosphate. Alternatively, the main component may bean aliphatic amine salt, for example, a salt of an organoacid phosphateand an alkylamine such as a dialkylamine. The alkyl amine phosphateadducts may be made in the same way as the aromatic amine adducts. Apreferred salt of this kind is the mono-/di-hexyl acid phosphate salt oflong chain (C₁₁-C₁₄) alkylamines which can be made into an adduct withTTZ in this way for use in the present compositions. The adduct canrange from 1:3 to 3:1 (mole) with the preferred adduct having a 75:25ratio (weight) of the TTZ and the long chain alky/organoacid phosphatesalt.

The TTZ amine phosphate salt adduct is typically used in relativelysmall amounts below about 5 wt. % and normally from about 0.1 to 1 wt.%, e.g. about 0.25 wt. %, is adequate when used in combination with thetrihydrocarbyl phosphate, e.g. cresyl diphenylphosphate, component inorder to give a good balance of anti-wear and anti-rust properties.Normally the CDP and the TTZ adduct are used in a weight ratio from 2:1to 5:1.

Additional anti-rust additives may also be used. Metal deactivatorswhich are commercially available and useful for this purpose, include,for example, the N,N-disubstituted aminomethyl-1,2,4-triazoles, and theN,N-disubstituted amino methyl-benzotriazoles. The N,N-disubstitutedaminomethyl-1,2,4-triazoles can be prepared by a known method, namely bereacting a 1,2,4-triazole with formaldehyde and an amine, as describedin U.S. Pat. No. 4,734,209. The N,N-disubstitutedaminomethyl-benzotriazole can be similarly obtained by reacting abenzotriazole with formaldehyde and an amine, as described in U.S. Pat.No. 4,701,273. Preferably, the metal deactivator is1-[bis(2-ethylhexyl)aminomethyl]-1,2,4-triazole or1-[bis(2-ethylhexyl)aminomethyl]-4-methylbenzotriazole (adduct oftolyltriazole:formaldehyde:di-2-ethylhexylamine (1:1:1 m)), which arecommercially available. Other rust inhibitors which may be used toconfer additional rust protection include the succinimde derivativessuch as the higher alkyl substituted amides of dodecylene succinic acid,which are also commercially, the higher alkyl substituted amides ofdodecenyl succinic acid such as the tetrapropenylsuccinic monoesters(commercially available) and imidazoline succinic anhydride derivatives,e.g. the imidazoline derivatives of tetrapropenyl succinic anhydride.Normally, these additional rust inhibitors will be used in relativelysmall amounts below 2 wt. % although for certain applications e.g. inpaper-making machinery oils, amounts up to about 5 wt. % may be employedif necessary.

The oils may also include other conventional additives, according toparticular service requirements, for example dispersants, detergents,friction modifiers, traction improving additives, demulsifiers,defoamants, chromophores (dyes), haze inhibitors, according toapplication, all of which may be blended according to conventionalmethods using commercially available materials.

As noted above, the present lubricating oils have superior propertiesand performance features. Examples of the good propertiesinclude—excellent viscometrics, high VI, low pour point, superior lowtemperature viscosities, thermal oxidative stability, etc. Theseproperties can be measured by many standard or special test. Usually,the kinematic viscosity were measured by ASTM D445. VI can be calculatedby ASTM D2270. Pour point of a lubricant can be measured by ASTM D97method. Cloud point of lubricant can be measured by ASTM D2500 method.Saybolt Universal Viscosity can be calculated by ASTM D2161 method. Lowtemperature, low-shear-rate viscosity of many gear oils, transmissionoils, industrial lubricants and engine oils can be measured byBrookfield viscometer according to the ASTM D2983 method. Alternatively,when a range of viscosities at low temperatures are required, a scanningBrookfield viscosity can be obtained according to ASTM D5133 method.Viscosity at high temperature high shear rate can be measured by D4624,D5481, or D4741 method.

Good antiwear characteristics are indicated by performance in the FZGScuffing test (DIN 51534), with fail stage values of at least 8, moreusually in the range of 9 to 13 or even higher. The FZG test isindicative of performance for steel-on-steel contact as encountered innormal gear sets; good performance in this test indicates that good spurgear performance can be expected. The higher FZG test values aretypically achieved with the higher viscosity grade oils, e.g. ISO 100and higher will have an FZG value of 12 or higher, even 13 or higher, incomparison with values of 9 to 12 for grades below ISO 100. Values of 13or higher (A/16.6/90) or 12 and higher (A/8.3/140) may be achieved withISO grades of 300 and higher.

The anti-wear performance may also be indicated by a 4-Ball (ASTM D4172) wear test value of not more than 0.35 mm maximum scar diameter(steel on steel, 1 hr, 180 rpm, 54° C., 20 Kg/cm²) with values of notmore than 0.30 mm being readily attainable. 4-ball EP Weld values of 120or higher, typically 150 or higher may be achieved. ASTM 4-Ballsteel-on-bronze values of 0.07 mm (wear scar diameter) are typical.

The rust inhibition performance is indicated by a Pass in ASTM D 665Bwith synthetic sea water. Copper Strip Corrosion (ASTM D130) at 24hours, 121° C., is typically 2A maximum, usually 1B or 2A.

Excellent high temperature oxidation performance is shown by a number ofperformance criteria including low viscosity change, low acid numberchange and low corrosion or sludge deposit. A catalytic oxidation testhas been developed to evaluate all these important criteria in onesingle test. In this catalytic oxidation test, 50 ml. of oil is placedin a glass tube together with iron, copper, and aluminum catalysts and aweight lead corrosion specimen. The cell and its contents are placed ina bath maintained at 163° C. and 10 liters/hr of dried air is bubbledthrough the sample for 40 hours. The cell is removed from the bath andthe catalyst assembly is removed from the cell. The oil is examined forthe presence of sludge and the change in Neutralization Number (ASTM D664) and Kinematic Viscosity at 100° C. (ASTM D 445) are determined. Thelead specimen is cleaned and weighed to determine the loss in weight.Test values of no more than 5 mg. KOH (DELTA TAN, at 163° C., 120 hrs.)are characteristic of the present compositions with values below 3 mg.KOH or even lower frequently—typically less than 0 mg. KOH beingobtainable. Viscosity increase in the catalytic oxidation test istypically not more than 15% and may be as low as 8-10%.

Good oxidation resistance is also shown by the TOST values attained(ASTM D943) of at least 8,000 hours, usually at least 10,000 hours, withTOST sludge (1,000 hours) being no more than 1 wt. percent, usually nomore than 0.5 wt %. Oxidation stability can also be measured by othermethods, such as ASTM D2272.

The superior shear stability of the oils described in this invention canalso be measured by many shear stability tests. Examples are Kurt Orbahndiesel injector test (ASTM 3945) or ASTM D5275 method. Another test forthe shear stability is the tapered roller bearing shear test (CECL-45-T/C method). It can also be measured by a sonic shear stabilitytest (ASTM D2603 method). Shear stability is important for manyindustrial oil operations. Higher shear stability means the oil does notlose its viscosity at high shear. Such shear-stable oil can offer betterprotection under more severe operation conditions. The oil compositionsdescribed in this invention have superior shear stability for industrialoil applications.

The tendency of lubricating oils to foam can be a serious problem insystems such as gearing, high volume pumping, circulating lubricationand splash lubrication, etc. Foam formation in lubricant oils may causeinadequate lubrication, cavitation and overflow loss of lubricant,leading to mechanical failure. Therefore, it is important to control thefoam property of a lubricant oil. This is especially important forindustrial lubricants. Many methods were developed to measure thefoaming tendency of lubricant. For example, in a Mixmaster foam method,550 gram of test oil is charged into the container of a heavy dutyMixmater blender. The beater of the blender was then agitated at 750 rpmfor five minutes. The beater is stopped, lifted out of the oil and allowany oil to drain back into the container for 20 seconds. Then measurethe total foam volume in ml. This is the foam volume at time 0 minutes.Then after 5, 10, 20, 30, 40, etc. minutes, measure the foam volume tojudge how fast the foam volume dissipate. Usually the test oil has goodfoam property if it produces less foam at the end of the 5 minutes ofagitation and/or the faster the foam dissipates after the agitationstops. The lubricant formulated using HVI-PAO usually have superior foamproperty. Furthermore, the aged or contaminated lubricants based onHVI-PAO also have much better foam property than conventionalformulations. Other foaming tests include ASTM D892 method—FoamCharacteristics of Lubricating Oils.

Energy efficiency is becoming a more important factor in modernmachinery. Equipment builders are looking for ways to improve theequipment's energy efficiency, reduce power consumption, reduce frictionloss, etc. For example, refrigerator builders, consumers and governmentagencies are demanding energy efficient compressors for refrigerationunits. Government mandates minimum energy efficiency for automobiles.Gear operators are demanding more efficient gears with lower energyconsumption, lower operating temperature, etc. A lubricant can affectthe energy efficiency of a machinery system in many ways. For example,lower viscosity lubricants with specified protection level will havelower viscous drag, thus less energy loss and better efficiency.Lubricants with lower frictional coefficients usually have better energyefficiency. Lubricants that produce excessive foaming reduce thevolumetric efficiency. For example, on the downstroke of the piston, thefoamy layer is compacted. This compaction absorbs energy and thusreduces the energy available for useful work. The lubricants disclosedin this invention have many of these energy efficient characteristics.

Energy efficiency of industrial oil is best tested under operatingconditions. Such comparisons can be meaningfully made by usingside-by-side comparison. Examples of such results are reported in apaper “Development and Performance Advantages of Industrial, Automotiveand Aviation Synthetic Lubricants” Journal of Synthetic Lubrication, [1]p. 6-33 by D. A. Law and J. R. Lohuis, J. Y Breau, A. J. Harlow and M.Rochette.

Applications

The lubricating oils or grease of the present invention may be used forthe lubrication of rolling element bearings (e.g., ball bearings),gears, circulation lubrication system, hydraulics, compressors used tocompress gas (such as reciprocating, rotary and turbo-type aircompressors, gas turbine or other process gas compressors) or tocompress liquids (such as refrigerator compressors), vacuum pump ormetal working machinery, as well as electrical applications, such as forlubrication of electrical switch that produces an electrical arc duringon-off cycling or for electrical connectors.

The lubricant or grease components disclosed in this invention are mostsuitable for applications in industrial machinery where one of more thefollowing characteristics are desirable: wide temperature range, stableand reliable operation, superior protection, extended operation period,energy efficient. The present oils are characterized by an excellentbalance of performance properties including superior high and lowtemperature viscosities, flowability, excellent foam property, shearstability, and improved anti-wear characteristics, thermal and oxidativestability, low friction, low traction. They may find utility as gearoils, bearing oil, circulating oils, compressor oils, hydraulic oils,turbine oils, grease for all kinds of machinery, as well as in otherapplications, for example, in wet clutch systems, blower bearings, windturbine gear box, coal pulverizer drives, cooling tower gearboxes, kilndrives, paper machine drives and rotary screw compressors.

EXPERIMENTAL

The following examples are meant to illustrate the present invention andprovide a comparison with other methods and the products producedtherefrom. Numerous modifications and variations are possible and it isto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

I. HVI-PAOs From Non-Metallocene Catalysts

Preparation of the HVI-PAOs set forth in Table 1 below was described inU.S. Pat. No. 4,827,064. In this process, fluids with 100° C. viscosityranging from 5 to 3000 cSt were prepared in high yields. Threerepresentative examples of these fluids used for product formulationwere summarized in Table 1, below.

TABLE 1 Properties of HVI-PAO Sample 1 Sample 2 Sample 3 100° C. vis,cSt 18.5 145 298 VI 165 214 246 Pour Point, ° C. −55 −40 −32

II. HVI-PAO by Metallocene Catalysts

Sample 4. To a 500 ml flask, charge toluene (20 grams),1,3-dimethylcyclopentadienyl zirconium dichloride (0.01 gram) and 10%MAO in toluene solution (20.1 grams) under inert atmosphere. Add1-decene (100 gram) slowly into the catalyst mixture from additionfunnel while maintaining reaction temperature at 20-25° C. Let reactionmixture stir for 16 hours. Quench catalyst with 3 ml water and basicalumina. Filter to remove solids. Distill the liquid at 140° C/<1millitorr to remove any C20 and lighter components to provide lubesample. The lube yield is 92 wt. %. The lube has the followingproperties: 100° C. Visc=312 cSt, 40° C. visc=3259 cSt and VI=250. Thislube was further hydrogenated at standard typical hydrogenationconditions to give finished product.

Sample 5. This sample was prepared in a similar manner as Sample 4,except dimethysilyl bis[cyclopentadienyl]zirconium dichloride was usedas catalyst. The lube product has the following properties: 100° C.Visc=8.96 cSt, 40° C. visc=49.32 cSt and VI=164. The lube afterhydrogenation under standard conditions can be used in industrial lubeformulation.

III. Fully Synthetic Hydraulic Oil Formulations

Fully synthetic hydraulic oils were formulated containing HVI-PAO madein Sample 3, above, together with other synthetic base stocks. Theirproperties are summarized in Example 1 to 3 in Table 2. In a comparativeformulation Example 4 to 6, similar synthetic hydraulic oils wereformulated using a high viscosity PAO, SpectraSyn™ 40, available fromExxonMobil Chemical Co., together with the same synthetic base stocksused in Examples 1 to 3. These other basestocks included standardbasestocks typically added to commercial products and include lowviscosity ester fluids of 2 to 6 cSt in 20 to 30 wt % and low viscosityPAO fluids of 3 to 7 cSt in 20 to 70 wt %. The exact viscosity gradesand the amounts of the low viscosity ester and PAO fluids were chosen tomeet the specification of the finished lubricant viscosity grades, whichis fully within the skill of the ordinary artisan.

In all the formulations, a standard additive package containing properbalance of amine and phenolic antioxidants, de-foamants, corrosioninhibitor, rust inhibitor, metal deactivators, anti-wear agents anddetergent/dispersants was used.

The hydraulic oils based on the new HVI-PAO (Example 1 to 3) have VImore than 200, which is about 60 units higher than the VI of comparativeoils (Example 4 to 6). Furthermore, the predicted viscosities at 150° C.for oil Examples 1-3 are higher than those for oil Example 4-6. Thepredicted low temperature viscosity at −40° C. for Examples 1-3 are muchlower than those of Examples 4-6. Yet, Example 1 to 3 oils havecomparable shear stability as comparative example, as measured by KurtOrbhan shear stability test (ASTM D3945).

This set of examples demonstrated that, at the same shear stabilitylevel, oils formulated with the new base stocks have much improved highand low temperature properties than oil formulated with commercial PAO,as indicated by higher VI and more stable high and low temperatureviscosities.

TABLE 2 Lube properties of fully synthetic hydraulic oils Example 1 2 34 5 6 ISO vis grade 32 46 100 32 46 100 Wt % Sample 3 18 23 40 0 0 0HVI-PAO Wt % conventional PAO 0 0 0 5 20 52 Wt % Other base stocks (a)balance balance balance balance balance Balance Wt % Additives (b) 2.812.81 2.81 2.81 2.81 2.81 Visc at 40° C., cSt 35.6 45.0 103.8 32.0 45.9103.2 Visc at 100° C., cSt 7.96 9.76 20.0 6.10 8.02 14.82 VI 206 210 217141 148 149 Predicted Visc at 3.77 4.53 8.59 2.78 3.50 5.85 150° C., cStPredicted Visc 4730 5890 14130 14016 23868 78257 at −40° C., cSt % 100°C. visc loss 0.21 −0.34 1.45 0.44 0.18 0.40 (ASTM D3945) (a) - Otherbase stocks including 30 wt % ester fluid of 2.7 cS ester fluid. Theremaining balance is a 4 cS PAO fluid. (b) The additive package is atypical hydraulic additive package containing proper balanced amount ofphenolic or aromatic amine type antioxidant, antiwear additives, such asZDDP, friction modifiers and/or corrosion inhibitor. Examples ofadditives used in literature can be found in U.S. Pat. No. 4,537,696,although the exact components and concentration used here are differentfrom the previous example.

IV. Semi-Synthetic Hydraulic Oil Formulations

The HVI-PAO can also be used to blend with conventional mineral oil togive semi-synthetic lubricants with performance advantages overconventional viscosity improver. Semi-synthetic hydraulic oilformulations were formulated, Example 7 and 8 (Table 3), using adifferent amount of Sample 2, above, a 145 cSt oil, to give twoviscosity grades. Example 7 is lower vis grade. Example 8 is higher visgrade. The example 7 oil has comparable viscosity grade to the twocommercial hydraulic oils (Example 9 and 10), using a conventional VIimprover, Acryloid™ 956 available from Rohm and Haas. In all theseexamples, the remaining components are conventional mineral oil which isa solvent refined paraffinic neutral 100 SUS mineral oil. In example 7,a small amount of a 60 SUS naphthenic oil was added in order to bringthe viscosity and VI to be comparable to example 9 and 10. These mineraloil base stocks are commonly available from any of the major lubricantrefiners or distributors. When all these lubricants were subjected toTapered Roller Bearing (TRB) Shear Test (a standard CEC L-45-T/C test),Example 7 and 8 based on HVI-PAO have less 40 or 100° C. viscosity lossthan the oils formulated using VI improver (Example 9 and 10).Furthermore, Example 7 and 8 oils have much lower loss of VI as shown inTable 3. This set of data indicated that oils with the new HVI-PAO atsimilar or even high viscosity have better shear stability than oilswith commercial VI improver.

TABLE 3 Lube properties of semi-synthetic hydraulic oils Example 7 8 910 Wt % Sample 2 HVI-PAO 20 30 0 0 Wt % VI Improver (a) 0 0 6 7.5 Wt %Conventional 80 70 94 92.5 Mineral Oils (b) Visc at 40° C., cSt 45.296.6 44.71 44.72 Visc at 100° C., cSt 8.0 14.4 7.7 8.0 VI 152 153 142153 After TRB test Visc at 40° C., cSt 38.32 86.40 39.34 39.35 Visc at100° C., cSt 6.96 12.28 6.42 6.66 VI 144 137 117 122 % 100° C. Vis Loss13 14 17 17 % 40° C. Visc Loss 15 14 17 17 Δ VI loss 8 18 25 31 (a) TheVI improveris a conventional methylmethacrylate polymer. (b) The mineraloil is a combination of a 4 cS paraffinic solvent dewaxed base stock anda 3 cS naphthenic base stock

V. Synthetic Industrial Circulation Oil

Synthetic industrial circulation oils, Examples 11 to 14, of vis gradeISO 460 were formulated using the HVI-PAO from Sample 2, above, or witha conventional PAO with highest available viscosity, SpectraSyn™ 100,together with 20 wt % of a polar base stock, an alkylated naphthaleneSynesstic™ 5, also available from ExxonMobil Chemical Co. Theformulation also contains 1.75 wt % of an additive package commonly usedby lube formulators containing proper balanced amount of amine andphenolic antioxidants, anti-wear and extreme-present additivescomprising ZnDDP, cresyl phosphates, phosphates or phosphonates,dispersant, detergents, corrosion inhibitors, metal passivators,demulsifier for improved water separability, clarifying agents toimprove clarity, and colorant. The final viscosities of theseformulations all met the specification of IS0460 vis grade. Examples 11and 12 compare formulations with HVI-PAO vs. conventional PAO when nodefoamant is added to the finished formulation. Example 13 and 14compare formulations with HVI-PAO vs. conventional PAO when 200 ppm ofan defoamant DCF200 available from Dow Chemical Co. in a pre-preparedpackage was added. Other additive components are identical.

The example 11 oil, when tested in Mixmaster Foam Test described earlierin the test description section, showed 16% foam volume at 0 minutesafter agitation was stopped and 0% foam volume 5 minutes after agitationwas stopped.

In comparison, when a similar ISO 460 synthetic circulation oil wasformulated using conventional high viscosity PAO (Example 12, Table 4),the initial foam volume was 40% at 0 minutes after agitation wasstopped. The foam volume remained at 38% at ten minutes after agitationwas stopped. This shows that the new HVI-PAO based oil is less foaming.In a similar formulation, when 200 ppm of a typical commercial siliconedefoamant DCF 200 from Dow Chemical Co. was added to the formulation,the circulation oil formulated with the new HIV-PAO (Example 13, Table4) still have much less foam than the conventional PAO-based oil(Example 14, Table 4).

TABLE 4 Lube properties of synthetic circulation oils Example 11 12 1314 Wt % Sample HVI-PAO(a) 78.25 0 78.25 0 Wt % conventional PAO(b) 078.25 0 78.25 Defoamant concentration, ppm(c) 0 0 200 200 Wt % otherbase stock(d) 20 20 20 20 Wt % additives(e) 1.75 1.75 1.75 1.75 % FoamVolume At 0 minutes after mixing stopped 16 40 5 28 At 5 minutes aftermixing stopped 0 38 0 23 (a)HVI-PAO used in these experiments contain22.25 wt % Sample 1 HVI-PAO and 56 wt % Sample 2 HVI-PAO (b)ConventionalPAO used in these experiments contain 20 wt % 40 cSt PAO and 58.25 wt %100 cSt PAO, both are available from ExxonMobil Chemical Co. (c)Thedefoamant is DC200 from Dow Chemical Co., a polysilozane polymer of60,000 molecular weight (d)The other base stock used is a 5.5 cStdi-basic ester fluid available from ExxonMobil Chemical Co. (e)Theadditive package used in this formulation contains typical antioxidant,metal deactivator, anti-rust and anti-wear additives in proper balancedamount A typical additives package can be found in U.S. Pat. No.6,180,575.

When tested in a cone drive worm gear, the Example 11 oil showed ahigher savings benefits than comparative Example 12 oil, as summarizedin following table. More discussion and references about this test canbe found in Journal of Synthetic Lubrication, Vol. 1, No. 1, April 1984,page 6:

% Benefit relative % Benefit relative to mineral to mineral oil oil byExample 12 oil - by Example 11 oil comparative sample At 100% load 11.811.0 At 150% load 10.0 9.6

The following set of experiments demonstrated that the Example 13 oilbased on this invention had much better foaming property even when oilwas severely aged relative to the non-HVI-PAO basestock. In this set ofexperiments, Example 13 and 14 oils were aged by cycling the oil (60ml/hour) through an autoclave with air (100 cc/minute) at 200° C., 250psi and 3500 rpm. This process simulated the aging process of oil duringsevere operation for extended time. During this accelerated agingprocess in the autoclave, oil viscosities increased and samples weretake from the autoclave to measure their properties, especiallyregarding the foaming properties. The % foam volumes for each oil agedfor different time were summarized in the following tables. As thesedata demonstrated that Example 13 oils have much less foam even aftersevere aging. Even after more than 60 hours of oxidation, the oil stillhas less foam, 5 ml, than the comparative example 14 without any agingwhich has a foam volume of 28 ml at the same foam testing time.

0 Aging time, hrs (fresh sample) 7.8 27.8 47.1 67.1 Foam volume* for 0 08 5 5 Example 13 0 Aging time, hrs (fresh sample) 14.6 30.9 50.4 Foamvolume* for 28 48 53 56 Example 14 *Foam volume was measured 5 minutesafter agitation was stopped.

The following set of experiments demonstrated that the oil based on theHVI-PAO are more resistant to foaming even after it is badlycontaminated with other aged oil or with impurity. When a knowncontaminant, a used and aged marine engine oil Mobilgard 570, 0.5 wt %,was added to Example 13 oil, the foam volume (5 minutes after agitationstopped) increased from 0% to 2%. When the same contaminant was added toExample 14 oil, the foam volume increased from 23% to 47% —a much biggerincrease than Example 13 oil.

Wide cross-graded synthetic automotive gear oils were also formulatedusing the Sample 2 HVI-PAO versus conventional high viscosity PAO,SpectraSyn™ 100 available from ExxonMobil Chemical Co. (Table 5, example17 to 20). In this formulation, in addition to the PAO or HVI-PAO basestocks, other base stocks with higher polarity, especially Group V basestocks, including esters or alkylated aromatics of lower viscosity 1.3to 6 cS, are also added. The amount of each base stock used in the finalformulation is adjusted to achieve same viscosity at 100° C. In thisformulation, 9-10 wt % of proper balanced amount of additives is alsoused. The additive package usually include anti-oxidants, anti-wear andextreme pressure additives, rust and corrosion inhibitors, frictionmodifiers, defoamants, viscosity modifiers, dispersants and detergents,etc. As the data demonstrated that the gear oil based on HVI-PAO havemuch higher VI and lower low temperature Brookfield viscosity at −40° C.This high VI and low viscosity at low temperature is beneficial forenergy efficiency and wear protection.

TABLE 5 Lube properties of synthetic automotive gear oils Example 17 1819 20 Vis grade 75W-90 75W-90 75W-140 75W-140 Wt % HVI-PAO 53.4 0 60 0Wt % conventional PAO 0 54.2 0 60 Wt % other base stock 36.3 36.3 30 30Wt % additives 9.3 9.3 10 10 Visc at 100° C., cSt 15.7 15.7 24.8 26.3 VI174 151 203 174 Pour point, ° C. <−65 −55 <−65 −55 Brookfield viscosity61,500 116,600 54,000 147,600 @ −40° C., cP

A synthetic paper machine oil formulated using the new HVI-PAO (Example21) had much lower foaming tendency than the comparative oil formulatedwith conventional high vis PAO, SpectraSyn™ 100 available fromExxonMobil Chemical Co. (Example 22), Table 6. In a ASTM foam test (D892method), Example 21 generated much less initial foam volume and settlingfoam volume than comparative Example 22 at 24°, 93.5° and 24° C. inSequence 1, 2 and 3 tests.

TABLE 6 Properties of synthetic paper machine oils Example 21 22 Wt %HVI-PAO 52.0 0 Wt % conventional PAO 0 48.5 Wt % other base stock 45.1548.4 Wt % additives 2.85 3.1 Visc at 100° C., cSt 31.37 26.22 Visc at40° C., cSt 244.3 232.5 Foam by ASTM D892 method Seq 1 (ml/min/ml) (a)250/9.15/0 600/10/360 Seq 2 (ml/min/ml) (b) 80/1.24/0 216/1.53/0 Seq 3(ml/min/ml) (c) 210/10/10 550/10/135 (a) - 24° C., (b) - 93.5° C., (c) -24° C.

These examples demonstrated that HVI-PAO can be used broadly in manyindustrial oil and greases with performance advantages over conventionallube compositions.

Trade names used herein are indicated by a ™ symbol or ® symbol,indicating that the names may be protected by certain trademark rights,e.g., they may be registered trademarks in various jurisdictions.

All patents and patent applications, test procedures (such as ASTMmethods, UL methods, and the like), and other documents cited herein arefully incorporated by reference to the extent such disclosure is notinconsistent with this invention and for all jurisdictions in which suchincorporation is permitted.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present invention,including all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

The invention has been described above with reference to numerousembodiments and specific examples. Many variations will suggestthemselves to those skilled in this art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims.

1. A formulated industrial oil, said oil having an ISO viscosity gradeof 2 to 46,000 and comprising: (a) 1 to 95 wt % of at least one HVI-PAO;(b) 5 to 50 wt % of at least one first basestock selected from Group Ibasestocks having a viscosity range of from 3 cSt to 50 cSt, Group IIand Group III hydroprocessed basestocks, and a Group IV PAO having a VIof about 130 or less; and (c) 1 to 50 wt % of a second basestockselected from Group V basestocks.
 2. The formulated industrial oilaccording to claim 1, said oil does not contain any added polymericthickeners or VI improver.
 3. The formulated industrial oil according toclaim 1, wherein said HVI-PAO is obtained by oligomerizing at least onealpha olefin using a catalyst selected from reduced metal oxides,metallocenes, and Zeigler-Natta catalyst.
 4. The formulated industrialoil according to claim 1, further comprising at least one additiveselected from anti-oxidants, anti-wear agents, extreme pressure agents,defoamants, detergent/dispersant, rust and corrosion inhibitors, anddemulsifiers.
 5. The formulated industrial oil according to claim 1,wherein said HVI-PAO is characterized by a viscosity index (VI) greaterthan 160, as measured by ASTM D2270, and by at least one of thefollowing: a branch ratio of less than 0.19, a weight average molecularweight of between 300 and 45,000, a number average molecular weight ofbetween 300 and 18,000, a molecular weight distribution of between 1 and5, a pour point below −15° C., a bromine number of less than 3, a carbonnumber ranging from C30 to C1300, and a kinematic viscosity measured at100° C. ranging from about 3 cSt to about 15,000 cSt, as measured byASTM D445.
 6. The formulated industrial oil according to claim 1,wherein said Group V basestock is selected from alkylated aromatics,polyalkylene glycols, esters, and mixtures thereof.
 7. The formulatedindustrial oil according to claim 1, wherein said Group V basestock ispresent in the amount of about 1 to 20 wt %.
 8. The formulatedindustrial oil according to claim 1, wherein said Group V basestock ispresent in the amount of about 5 to 25 wt %.
 9. In an apparatuscomprising a rolling element bearing lubricated by an industrial oil,the improvement comprising an oil according to claim
 1. 10. In a gearsystem, circulation lubrication system, hydraulic system, compressorsystem, vacuum pump, metal working machinery, electrical switch orconnector comprising a lubricating oil, the improvement comprising anoil according to claim
 1. 11. The formulated industrial oil according toclaim 1, wherein (a) said HVI-PAO is present in the amount of 15 to 50wt %, (b) said first basestock is present in the amount of 5 to 50 wt %,and (c) said second basestock selected from Group V basestock is presentin the amount of 5 to 50 wt %.
 12. The formulated industrial oilaccording to claim 11, wherein said first basestock is a Group IV PAOhaving a VI of about 130 or less.
 13. The formulated industrial oilaccording to claim 11, wherein no polymeric thickeners or VI improver isadded.